Rational construction the composite of graphene and hierarchical structure assembled by Fe₂O₃ nanosheets for lithium storage

Taking the advantage of hierarchical nanostructures into consideration, herein a facile and template free approach to achieve hierarchical microspheres assembled from the α-Fe₂O₃ nanosheet was formulated. The followed freeze-drying treatment is employed to realize the construction of nanostructured Fe₂O₃/graphene composite. The unique hierarchical structure of α-Fe₂O₃ combined with the flexible graphene layer not only effectively buffer the volume expansion during the cycling process, but also promote the transport of lithium ion and electron through three-dimensional networks when being assessed for lithium ion battery. The as-obtained composite exhibits significantly enhanced cycling stability (1850 mA h g⁻¹ after 190 cycles at the current of 300 mA g⁻¹) and superior rate performance (around 520 mA h g⁻¹ for the current of 5000 mA g⁻¹). The obtained-results illustrate that the rational designing of the nanostructured composite can result in the fast lithium insertion/de-insertion in lithium ion batteries which mimic merits seen in high-power electrochemical capacitors.